Mooring Cell Sheet Pile Repair

PROJECT TITLE: Mooring Cell Sheet Pile Repair

PROJECT LOCATION: Ohio River, Louisville, Kentucky

CLIENT: Busy River Port

Problem

Bulldog Diving was summoned to perform a Sheet Pile repair and mooring ring replacement on a mooring cell. We were chosen for our record of developing innovative approaches to work that our industry peers shy away from when it gets difficult. For this project, we developed a repair for the front of a mooring cell that involves welding verticals and backfilling with concrete.

A loaded barge weighs between 1,500-2,000 tons, and a typical tow may run from 10 to 20 barges at a time. This creates a tremendous amount of mass that a mooring cell is expected to handle. If a tie-up is done successfully, the cell will avoid impact damage.  Eventually, though, even under normal wear and tear, barges will wear the front knuckles off the sheet pile.

With the outer knuckle gone, resulting internal pressure will cause the knuckle to separate, which, in turn, releases the cell ballast. At that point the mooring cell becomes not just non-functional, but dangerous, because it becomes unstable and could founder or even block parts of the waterway.

Solution

Because the structure of a mooring cell is layered, repairing parts of it can be involved.

Most sheet piling used for a mooring cell is 3/8-inch thick upon original installation. We installed a 3/8-in. rolled steel plate over the damaged area. Backfilling the cell with concrete behind the repair unites the repair plate and the cell, in effect restoring near-original strength to the structure.

Rolling a sheet of steel to fit a cell that has weathered decades of abuse from the mass of multiple barges posed some challenges, as did welding the verticals to older, beat-up steel. Then sealing the bottom of the repair to the cell in order to backfill with concrete… all of these are extremely difficult tasks.

Result

With the repair plate in place, the owners were able to resume normal use of the mooring cell in their very busy port for years to come. This affects the business of every customer using the port and, potentially, this mooring cell.